To achieve what you want you should make sure that your "BIOS" starts
with the watchdog enabled and with a very long watchdog heartbeat (so
that it doesn't need to get pinged). Then the kernel can boot and
userspace can start and then you can do the necessary with the
/dev/watchdog functionality. Only thing you need to take care of is
that you don't stop the watchdog (via a module param or something
similar) during the probe/init of the driver.
I believe we allready have a winbond driver doing that. Just checked:
it's w83697hf_wdt.c with the early_disable module parameter.
So, this is something that needs to be taken into account during
probe/init of the driver and for each watchdog that needs it.
And thus not for the first watchdog that get's registered.
Furthermore: not all watchdog devices have a heartbeat that is long
enough to achieve this functionality.
Okay, thanks for the clarification. So I will change the driver and add
an appropriate paramter to it instead as the winbond driver does.
Other drivers do the same, but don't even have a module parameter to
disable it if it is already running. They just ping the watchdog during
initialization to delay the timeout. w83627hf_wdt.c is an example.
Guenter
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